With the development and progress of science and technology, mobile electronic devices such as mobile phones, digital cameras, tablet computers, and notebook computers have become indispensable tools in people's lives. In order to effectively prevent the data inside the personal mobile electronic devices from being stolen, various protection methods have been devised accordingly, such as password verification, voiceprint identification, or fingerprint identification, wherein the fingerprint identification is widely used. In existing capacitive sensing devices, the capacitance variation generated by charging and discharging a capacitor is typically converted into original data value; however, since a distortion of the conversion voltage variation is caused by process offset or parasitic capacitance effect, errors or distortions in image processing are caused accordingly.
Therefore, how to provide a system for sensing capacitances to avoid occurrence of the above situation becomes one of the goals to be achieved in the industry.